Make sure attribute chains are evaluated safely

common/utils.py

@@ -7,3 +7,23 @@ def safe_division(numerator: int | float, denominator: int | float) -> int | flo
         return numerator / denominator
     except ZeroDivisionError:
         return 0
+    
+def safe_getattr(obj, attr_chain, default=None):
+    """
+    Safely get the nested attribute from an object.
+
+    Parameters:
+    obj (object): The object from which to retrieve the attribute.
+    attr_chain (str): The chain of attributes, separated by dots.
+    default: The default value to return if any attribute in the chain does not exist.
+
+    Returns:
+    The value of the nested attribute if it exists, otherwise the default value.
+    """
+    attrs = attr_chain.split('.')
+    for attr in attrs:
+        try:
+            obj = getattr(obj, attr)
+        except AttributeError:
+            return default
+    return obj

games/forms.py

@@ -1,5 +1,6 @@
 from django import forms
 from django.urls import reverse
+from common.utils import safe_getattr
 
 from games.models import Device, Edition, Game, Platform, Purchase, Session
 
@@ -45,8 +46,8 @@ class EditionChoiceField(forms.ModelChoiceField):
 class IncludePlatformSelect(forms.Select):
     def create_option(self, name, value, *args, **kwargs):
         option = super().create_option(name, value, *args, **kwargs)
-        if value:
+        if platform_id := safe_getattr(value, 'instance.platform.id'):
-            option["attrs"]["data-platform"] = value.instance.platform.id
+            option["attrs"]["data-platform"] = platform_id
         return option